gtroth

bobboinski

The highest pressure I've used with mine is about 17psi. I think if I had a corner that wouldn't flow any fluid at all I'd go to the old fashioned step on the brake pedal method. Less chance of making a big mess in the frunk.

steved0x

On the 9x6 platform.you can go to 20 psi, but try stepping on the brake pedal after you have opened the bleeder, that will put way more than 20 psi through the line and if there is a small blockage the pedal will clear it much better than the pressure from the motive. Also make sure the hose on the motive didn't get linked, i wasn't get any flow one time and the hose had linked.

mhm993

I normally pump to about 15-17 ibs

Try removing the bleeder and poking something through the hole.
Pain in the butt if its frozen on, but you can take off the metal line off the caliper and see what comes out.

NC TRACKRAT

If you're not getting any flow from both the inner and outer bleed nipples, you have some sort of blockage internally. Without any pressure from the MOTIVE, remove the inner bleed nipple and see if you have any fluid flow. If not, see if you can dislodge any build-up with a toothpick or similar tool. If that doesn't help, disconnect the brake line and confirm you have flow through the line to the caliper. Then you'll need to remove the caliper and flush whatever has clogged it.

AX993

In the workshop manual, Porsche says to attach a "bleeding device" and use 1.5 bar pressure. I don't know what the Porsche "bleeding device" is, but 1.5 bar is 21.76 psi so I pump my Motive to 20 -21 psi to bleed the brakes on my vacuum boosted C2 brake system. My 993's rear calipers bleed slower than the front.

The procedure is different for 993s with the hydraulic booster brake system such as C4 and RS but the "bleeding device" pressure is still 1.5 bar.
HTH

BobbyT

I use 20 psi on the Motive bleeder, and I had one bleed screw that wouldn't flow. I took it out and the screw was totally clogged. The passage in the bleed screw is T-shaped, so you may be able to open it fully with a tiny wire or straight pin and shop air. I wound up just replacing the clogged one--I had some new spares handy.

If brakes aren't bled over a long time, a waxy substance builds up and causes this clogging. I hate to think what it might do to the ABS unit. Bleed those brakes!

nine9six

... and don't forget the clutch slave or the ABS/ABD, if equipped!

BTW, it's not a matter of maximum pressure to the Motive Power bleeder, but rather the max pressure you want to put on the brake reservoir!

pp000830

You are using plenty of pressure, in my experience, it doesn't take much. I read once that one of the ways a brake hose fails is an internal wall rip will seal the hose. Also, a quick check can be to have someone press on the brake peddle while trying to bleed the offending caliper and see if it produces any flow. Ultimately one can disconnect the hard line to the hose that leads to the caliper and sees if flow can be observed. If you have not done this before be sure to use very high-quality hydraulic wrenches such as Snap-On or Craftsman, the inexpensive one's heads tend to flex and damage the fittings before they break the connection loose.
Other causes can be debris in the caliper from the casting or abrasives used to clean a remanufactured caliper. Also, the bleeder valve seat could conceivably be improperly positioned or distorted closing off the flow.